There are many vegetables suitable for planting in late summer/early fall, ready to be harvested in late fall/early winter. Here are a few examples!
Greens! – Arugula, Lettuce, Collards, Chard, Kale, Mustard Greens, and Spinach (Harvest before first frost!)
Broccoli and Cauliflower – Cover if danger of frost threatens
Beets, Radishes, and Turnips – Great root veggies
Onions, Scallions, and Garlic – Bunching onions are great for fall and to dry and store for winter
Herbs – Dill, Cilantro, Parsley, and Basil